Illumination device

ABSTRACT

An illumination device including a light source; a light scanner for changing a light path of light-source light; a light diffusion device having element diffusion devices; and a light-path adjustment device disposed on a light path of the light-source light, the light-path adjustment device having element adjustment devices corresponding to respective element diffusion devices, adjusting a light path of the light-source light. An incident position of the light-source light on the light-path adjustment device varies depending on a light path determined by the light scanner. An incident angle of the light-source light on each element diffusion device varies depending on an incident position on the element adjustment device corresponding to the element diffusion device. An emergent angle from each element diffusion device varies depending on the incident angle on the element diffusion device. Each element diffusion device illuminates an element illumination area corresponding to the element diffusion device.

TECHNICAL FIELD

The present invention relates to an illumination device.

BACKGROUND ART

As disclosed in JP2012-146621A, for example, an illumination deviceusing a coherent light source is widely used. A laser light source thatoscillates a laser light (laser beam) is typically used as the coherentlight source.

JP2012-146621A discloses a vehicle lighting tool. The vehicle lightingtool includes a light source, which can be formed by a laser oscillationdevice, and four hologram devices. The respective hologram devices aremoved by a rotary driving apparatus to be located on positions wherethey can receive a laser light from the light source. The respectivehologram devices diffract the laser light to achieve illumination in adesired light distribution pattern. By suitably selecting a hologramdevice which is irradiated with a laser light, illumination in apredetermined light distribution pattern can be achieved. In order toachieve illumination in a great number of light distribution patterns byusing this vehicle lighting tool, it is necessary to increase the numberof hologram devices that can be selectively irradiated with a laserlight. In this case, the structure and control of the device becomesignificantly complicated. Further, while it is necessary to ensurelight paths of incident light and emergent light for each hologramdevice, the number of hologram devices that are rotatably supportedabout one axis has an upper limit. Namely, the illumination device(lighting tool) disclosed in JP2012-146621A is difficult to performillumination in a great number of light distribution patterns.

DISCLOSURE OF THE INVENTION

The present invention has been made in consideration of the above point.The object of the present invention is to provide an illumination devicecapable of performing illumination in various light distributionpatterns by a simple structure.

An illumination device according to one embodiment of the disclosurecomprises:

a light source;

a light scanner capable of changing a light path of light-source lightemitted from the light source;

a light diffusion device having element diffusion devices that diffusethe light-source light; and

a light-path adjustment device disposed on a light path of thelight-source light from the light scanner up to the light diffusiondevice, the light-path adjustment device having element adjustmentdevices that are provided correspondingly to the respective elementdiffusion devices, and adjust a light path of the light-source lighttoward the corresponding element diffusion devices;

wherein:

an incident position of the light-source light on the light-pathadjustment device varies depending on a light path determined by thelight scanner;

an incident angle of the light-source light on each element diffusiondevice varies depending on an incident position on the elementadjustment device corresponding to the element diffusion device;

an emergent angle from each element diffusion device varies depending onthe incident angle; and

each element diffusion device illuminates an element illumination areacorresponding to the element diffusion device.

In the illumination device according to the one embodiment of thedisclosure, light emitted from each element adjustment device may travelalong one of light paths of convergent light fluxes to enter an elementdiffusion device corresponding to the element adjustment device.

In the illumination device according to the one embodiment of thedisclosure, element illumination areas corresponding to the respectiveelement diffusion devices may not be overlapped with one another.

In the illumination device according to the one embodiment of thedisclosure,

the light scanner may have a rotatable reflection device;

the reflection device may include reflection surfaces at positionssurrounding its rotational axis line; and

an angle defined by one reflection surface included in the reflectionsurfaces with respect to the rotational axis line may differ from anangle defined by at least another reflection surface included in thereflection surfaces with respect to the rotational axis line.

The illumination device according to the one embodiment of thedisclosure may further comprise a light condensing device disposed on alight path of the light-source light from the light scanner up to thelight-path adjustment device.

In the illumination device according to the one embodiment of thedisclosure, the light scanner may be located on a position based on afront-side focal point of the light condensing device.

In the illumination device according to the one embodiment of thedisclosure, the light-path adjustment device may have a lens arrayincluding unit lenses constituting the element adjustment devices.

In the illumination device according to the one embodiment of thedisclosure, each element diffusion device may be located on a positionbased on a rear-side focal point of a unit lens constituting acorresponding element adjustment device.

In the illumination device according to the one embodiment of thedisclosure, each element diffusion device may be located on a positionbased on a rear-side focal point of a unit lens constituting acorresponding element adjustment device.

In the illumination device according to the one embodiment of thedisclosure, each element diffusion device may be located on a positionapart from a unit lens, corresponding to said element diffusion device,by a focal point distance of said unit lens constituting an elementadjustment device.

In the illumination device according to the one embodiment of thedisclosure, each element adjustment device may allow the light-sourcelight to enter a specific area of a corresponding element diffusiondevice, irrespective of an incident position of the light-source lighton the element adjustment device.

In the illumination device according to the one embodiment of thedisclosure,

the light diffusion device may be a hologram storage medium, and

the element diffusion devices may be element holograms includinginterference fringe patterns different from one another.

In the illumination device according to the one embodiment of thedisclosure, the light diffusion device may be a lens array group havinglens arrays constituting the element diffusion devices.

The illumination device according to the one embodiment of thedisclosure may further comprises a control unit that controls emissionof light from the light source, depending on an incident positon of thelight-source light on the light adjustment device,

According to the one embodiment of the disclosure, the illuminationdevice of a simple structure can perform illumination in various lightdistribution patterns.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view schematically showing an overall structureof an illumination device, for explaining one embodiment of the presentinvention.

FIG. 2 is a plan view showing the illumination device of FIG. 1.

FIG. 3 is a partial side view showing the illumination device of FIG. 1.

FIG. 4 is a perspective view showing a light-path adjustment device anda light diffusion device.

FIG. 5 is a view showing light paths from the light-path adjustmentdevice up to an illumination area in the illumination device of FIG. 1.

MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described herebelow withreference to the drawings. In the drawings attached to thespecification, a scale size, an aspect ratio and so on are changed andexaggerated from the actual ones, for the convenience of easiness inillustration and understanding.

Further, terms specifying shapes, geometric conditions and theirdegrees, e.g., “parallel”, “perpendicular/orthogonal”, “same”, etc., arenot limited to their strict definitions, but are to be construed toinclude a range capable of exerting a similar function.

FIG. 1 is a perspective view showing an overall structure of anillumination device 10. The illumination device 10 illuminates anillumination area Z by using a coherent light such as a laser light(laser beam). The illumination device 10 includes, as a light source, alaser light source 15 that oscillates a laser light. The laser lightsource 15 oscillates a laser light which is a coherent light. Theillumination apparatus 10 includes a light scanner 20, a lightcondensing device 30, a light-path adjustment device 40 and a lightdiffusion device 50, which process light emitted from the laser lightsource 15. In the example shown in FIG. 1, the light scanner 20, thelight condensing device 30, the light-path adjustment device 40 and thelight diffusion device 50 are located in this order along a light pathof a laser light from the laser light source 15, and they process alaser light in this order. As described in detail below, theillumination device 10 described herein can illuminate the illuminationarea Z in various light distribution patterns, by means of opticalfunctions of the light-path adjustment device 40 and the light diffusiondevice 50, while the illumination device 10 has a simple structure.Herebelow, the respective constituent elements are described in series.

In the example shown in FIG. 1, the laser light source 15 has aplurality of light source units 17 that emit laser lights. The lightsource units 17 may be independently arranged, or may be a light sourcemodule formed by arranging the light source units 17 side by side on acommon substrate. For example, the light source units 17 have a firstlight source unit 17 a that oscillates a light having a red emissionwavelength range, a second light source unit 17 b that oscillates alight having a green emission wavelength range, and a third light sourceunit 17 c that oscillates a light having a blue emission wavelengthrange. According to this example, by overlapping three laser lightsemitted from the light source units 17 a, 17 b and 17 c, illuminationlights of various colors including a white illumination light can begenerated.

Although an example in which the laser light source 15 has the threelight source units 17 a, 17 b and 17 c having emission wavelength rangesdifferent from one another is described herebelow, the present inventionis not limited thereto. The laser light source 15 may have two lightunits 17 having emission wavelength ranges different from each other, orfour or more light units 17 having emission wavelength ranges differentfrom one another. In addition, in order to increase emission intensity,a plurality of the light source units 17 may be provided for eachemission wavelength range.

As shown in FIG. 1, the illumination device 10 includes an emissioncontrol unit 12 connected to the laser light source 15. The control unit12 discretely controls emission timings of laser lights emitted by thelaser light source 15, or illumination timings of the illumination area.In particular, the control unit 12 can switch emission of laser lightsand stop of emission of laser lights from the light source unit 17 a, 17b or 17 c, independently from other light source units. The control ofemitting or not emitting laser lights by the control unit 12 is carriedout based on scanning timings of a plurality of laser lights by thelight scanner 20, in other words, based on incident positions of a laserlight on the light-path adjustment device 40 and the light diffusiondevice 50. As described above, in the case where the laser light source15 can emit three laser lights, i.e., a red laser light, a blue laserlight and a green laser light, it is possible to generate anillumination light of a color that is a combination of given two or morecolors of red, blue and green, by controlling an emission timing of eachlaser light.

The control unit 12 may control an emission timing of a light from thelaser light source 15, may control an incident timing of a laser lightincident on the light diffusion device 50, or may control anillumination timing at which a laser light diffused by the lightdiffusion device 50 illuminates an illumination range. Herebelow, anexample in which the control unit 12 controls an emission timing of alight from the laser light source 15 is mainly described.

The emission control unit 12 may control whether a laser light isemitted from each light source unit 17 or not, i.e., ON/OFF of emission,or may switch blocking or not blocking of a light path of a laser lighthaving been emitted from each light source unit 17. In the latter case,light shutter units, not shown, may be disposed between the respectivelight source units 17 and the light scanner 20, such that passage andblockage of laser light can be switched by the light shutter units.

Next, the light scanner 20 is described. The light scanner 20 adjusts atraveling direction of a laser light emitted from the laser light source15. In the illustrated example, the light scanner 20 can change atraveling direction of a laser light with time. Due to the light pathadjustment of the light scanner 20, a laser light emitted from the laserlight source 15 scans the light condensing device 30, and further scansthe light-path adjustment device 40. In the example shown in FIGS. 1 and2, the light scanner 20 has a reflection device 21 that is rotatableabout a rotational axis line ra. The reflection device 21 includesreflection surfaces 22 at positions surrounding the rotational axis linera. In the illustrated example, the reflection device 21 is formed as apolygonal mirror having six reflection surfaces 22 a to 22 f. When thereflection device 21 is rotated about its central axis line as therotational axis line ra, a reflection direction of a light havingentered there from a certain direction can be changed cyclically. In theillustrated example, a laser light going out from the light scanner 20travels along one of light paths constituting divergent light fluxeswhose divergent point is the incident position on the light scanner 20.

The respective six reflection surfaces 22 a to 22 f of the reflectiondevice 21 are formed as flat surfaces. Thus, a light that entered thereflection device 21 from a certain direction and is reflected thererepeatedly travels along a path extending in a direction orthogonal tothe rotational axis line ra, on the light condensing device 30 and thelight-path adjustment device 40.

Further, in the illustrated example, values of angles defined by therespective reflection surfaces 22 a to 22 f with respect to therotational axis line ra are not uniform through the reflection surfaces22 a to 22 f. FIG. 3 is a view showing the reflection device 21 in asection passing through the rotational axis line ra. As shown in FIG. 3,an angle θa1 of the first reflection surface 22 a with respect to therotational axis line ra is inclined reversely to an angle θa6 of thesixth reflection surface relative to the rotational axis line ra, whichis indicated by two-dot chain lines, with the rotational axis line ra asa reference. As a result, incident positions of a light reflected by thereflection device 21 on the light condensing device 30 and thelight-path adjustment device 40 vary in a direction parallel to therotational axis line ra, depending on the fact that by which reflectionsurface 22 a to 22 f the light is reflected. Namely, in the illustratedexample, a scanning path of the laser light on the light condensingdevice 30 and a scanning path of the laser light on the light-pathadjustment device 40 vary two-dimensionally.

In the illustrated example, the light source units 17 a, 17 b and 17 care arranged in a direction parallel to the rotational axis line ra ofthe reflection device 12 (see FIG. 1). The reflection surface of thereflection device 21 has, along its rotational axis line ra, a firstreflection part 21 a, a second reflection part 21 b and a thirdreflection part 21 c. The first reflection part 21 a reflects a laserlight emitted from the first light source unit 17 a, and cyclicallychanges a traveling direction of the laser light in a plane parallel tothe rotational axis line ra. In addition, the second reflection part 21b reflects a laser light emitted from the second light source unit 17 b,and the third reflection unit 21 c reflects a laser light emitted fromthe third light source unit 17 c.

The light scanner 20 is not limited to the illustrated reflection device21. It is possible to use, as the light scanner 20, MEMS (microelectromechanical systems) such as a digital micromirror device (DMD),for example. Further, the light scanner 20 may change a light path of alaser light only in one-dimensional direction, so that scanning paths ofa laser light on the light condensing device 30 and the light-pathadjustment device 40 define one straight line.

Next, the light condensing device 30 is described. A light going outfrom the light scanner 20 then enters the light condensing device 30.The light condensing device 30 is disposed on a light path of a laserlight from the light scanner 20 up to the light-path adjustment device40. The light condensing device 30 has an optical effect on a laserlight whose light path has been changed by the light scanner 20. In theillustrated example 30, the light condensing device 30 is formed by alight condensing lens 31 having a focal point. The light condensing lens31 is disposed on a light path of a laser light from the light scanner20 toward the light-path adjustment device 40.

In the illustrated example, as shown in FIG. 2, the light scanner 20 islocated on a position based on a front-side focal point Ff of the lightcondensing device 30. Herein, “a position based on the front-side focalpoint Ff” typically means that the light scanner 20 is positioned on thefront-side focal point Ff of the light condensing device 30. However, itis not exactly necessary that the light scanner 20 is located on thefront-side focal point Ff. The light scanner 20 may be located in thevicinity of the front-side focal point Ff. Also in this case, an effectof the light condensing device 30 described later can be obtained.

Particularly in the illustrated example, the reflection device 21constituting the light scanner 20 is disposed apart from the lightcondensing lens 31 by a focal distance of the light condensing lens 31along an optical axis of the light condensing lens 31. As describedabove, a laser light going out from the reflection device 21 travelsalong one of light paths constituting divergent light fluxes whosedivergent point is the reflection position in the reflection device 21.Thus, as shown in FIGS. 2 and 3, when a laser light incident on eachposition of the light condensing lens 31 transmits through the lightcondensing lens 31, an optical path of the laser light is adjusted so asto travel in a direction parallel to the optical axis of the lightcondensing lens 31. Namely, the light going out from each position ofthe light condensing device 30 travels along one of light pathsconstituting parallel light fluxes that travel in a direction parallelto the optical axis of the light condensing lens 31. Since the lightscanner 20 changes a traveling direction of a laser light with time, anincident position on the light condensing device 30 changes with time.

A plurality of the light condensing devices 30 may be providedcorrespondingly to the respective light source units 17 a, 17 b and 17 cincluded in the laser light source 15. Alternatively, a single lightcondensing device 30 capable of adjusting light paths of laser lightsfrom the light source units 17 a, 17 b and 17 c may be provided.

Next, the light-path adjustment device 40 is described. The light goingout from the light condensing device 30 then enters the light-pathadjustment device 40. The light-path adjustment device 40 is disposed ona light path of a laser light from the light condensing device 30 up tothe light diffusion device 50. The light-path adjustment device 40 isopposed to the light condensing device 30. The light-path adjustmentdevice 40 has an optical effect on a laser light whose light path hasbeen changed by the light condensing device 30. An incident position ofa laser light on the light-path adjustment device 40 varies depending onan incident position of the laser light on the light condensing device30, i.e., depending on a light path determined by the light scanner 20.

The light-path adjustment device 40 includes element adjustment devices45. The element adjustment devices 45 are arranged in a directionorthogonal to the optical axis of the light condensing lens 31. Thus, towhich one of the element adjustment devices 45 the laser light goes fromthe light condensing device 30 is determined depending on an incidentposition of the laser light on the light condensing device 30. Inaddition, an incident position of the laser light on one elementadjustment device 45 varies depending on an incident position of thelaser light on the light condensing device 30. In addition, an emergentangle α of the laser light from each element adjustment device 45 variesdepending on an incident position on the element adjustment device 45.As shown in FIGS. 2 and 3, the emergent angle α from the elementadjustment device 45 is an angle defined by a traveling direction of alight going out from the element adjustment device 45 with respect to anormal direction of the element adjustment device 45.

As shown in FIGS. 1 and 4, the illustrated light-path adjustment device40 is a lens array 41 including unit lenses 46 constituting the elementadjustment devices 45. The lens array 41 is located on a positionopposed to the light condensing lens 31 along the optical axis of thelight condensing lens 31 constituting the light condensing device 30.The unit lenses 46 included in the lens array 41 are positioned apartfrom the light condensing lens 31 by a certain distance along theoptical axis of the light condensing lens 31. Each unit lens 46 ispositioned such that its optical axis is parallel to the optical axis ofthe light condensing lens 31. As shown in FIG. 1, the element adjustmentdevices 45 are arranged in a direction orthogonal to the rotational axisline ra of the reflection device 21 constituting the light scanner 20.As a result, the light-path adjustment device 40 extends long in adirection orthogonal to the rotational axis line ra of the reflectiondevice 21.

In the illustrated example, as described above, the laser light goingout from the light condensing lens 31 travels in a direction parallel tothe optical axis of the light condensing lens 31. Namely, the lightincident on each element adjustment device 45 of the light-pathadjustment device 40 travels in a direction parallel to the optical axisof each element adjustment device 45. Thus, as shown in FIGS. 2 and 3,the laser light having transmitted through each element adjustmentdevice 45 travels toward a rear-side focal point Bf of the elementadjustment device 45. Namely, in the illustrated example, the laserlight going out from each element adjustment device 45 travels along oneof light paths constituting convergent light fluxes that converge on therear-side focal point Bf.

As shown in FIG. 1, a plurality of the light-path adjustment devices 40may be provided correspondingly to the light source units 17 a, 17 b and17 c included in the laser light source 15. Alternatively, a singlelight-path adjustment device 40 capable of adjusting light paths oflaser light from the lights source units 17 a, 17 b and 17 c may beprovided.

Next, the light diffusion device 50 is described. As shown in FIG. 1,the light diffusion device 50 diffuses an incident light, and directsthe diffused light toward the illumination area Z. The illumination areaZ is illuminated by the diffused light. The light diffusion device 50includes element diffusion devices 55. Each element diffusion device 55is provided correspondingly to any one of the element adjustment devices45. A laser light going out from the corresponding element adjustmententers each element diffusion device 55. The element diffusion device 55diffuses the incident light, and directs the diffused light df toward acorresponding element illumination area Zp. Namely, the elementillumination area Zp corresponding to the element diffusion device 55 isilluminated by the diffused light df going out from each elementdiffusion device 55.

The element illumination area Zp constitutes a part of the illuminationarea Z. At least a part of the element illumination area Zpcorresponding to one element diffusion device 55 is not overlapped withelement illumination areas Zp corresponding to the other elementdiffusion devices 55. Namely, a combination (an assembly) of the elementillumination areas Zp corresponding to the element diffusion devices 55is the illumination area Z that can be illuminated by the illuminationdevice 10. In other words, each position or each area of theillumination area Z belongs to any of the element illumination areas Zp.Thus, by using only the diffused light df from one or some of theelement diffusion device(s) 55, a pattern illumination in theillumination area Z can be achieved. By selecting an element diffusiondevice(s) 55 to be illuminated by a laser light, a light distributionpattern can be controlled.

Further, an emergent angle γ of a laser light from the element diffusiondevice 55 varies depending on an incident angle β of the laser light onthe element diffusion device 55. An incident angle β of the laser lighton each element diffusion device 55 depends on an emergent angle α ofthe laser light from the element adjustment device 45. As describedabove, an emergent angle α of the laser light from the elementadjustment device 45 varies depending on an incident position of thelaser light on the element adjustment device 45. Thus, an emergent angleγ of the laser light from the element diffusion device 55 variesdepending on an incident position of the laser light on the elementadjustment device 45 corresponding to the element diffusion device 55.Namely, the diffused light df diffused by the element diffusion device55 illuminates a part that is determined depending on the fact that onwhich position of the corresponding element adjustment device 45 thelaser light constituting the diffused light df is incident. Thus, byirradiating only one or some of the element adjustment device(s) 45 withthe laser light, a pattern illumination in the element illumination areaZp can be achieved. By selecting an area of the element adjustmentdevice 45 to be irradiated with the laser light, a light distributionpattern can be controlled.

The illumination area Z and the element illumination area Zp, whichconstitutes a part of the illumination area Z, are illumination areas ofnear fields that are overlappingly illuminated by respective elementdiffusion devices 55 in the light diffusion device 50. An illuminationrange of a far field is generally expressed as a diffusion angledistribution in an angular space, rather than an actual illuminationarea size. The terms “illumination area” and “element illumination area”in this specification include a diffusion angle range in an angularspace in addition to an actual illumination area (illumination range).Thus, a predetermined range illuminated by the illumination device 10 ofFIGS. 1 and 5 can be an area that is greatly larger than theillumination area Z of a near field shown in FIGS. 1 and 4.

An incident angle β on the element diffusion device 55 is an angledefined by a traveling direction of a light that enters the elementdiffusion device 55 with respect to the normal direction of the lightdiffusion device 50. On the other hand, an emergent angle γ from theelement diffusion device 55 is an angle defined by a traveling directionof a light going out from the element diffusion device 55 with respectto the normal direction of the light diffusion device 50. In thisembodiment, a light going out from the element diffusion device 55becomes a diffused light df. When a diffusion angle cannot be neglected,an emergent angle γ from the element diffusion device 55 is regarded asan angle defined by a direction in which a brightness peak of thediffusion light is generated, with respect to the normal direction ofthe light diffusion device 50.

As shown in FIGS. 1 and 4, in the illustrated light diffusion device 50,each element diffusion device 55 is disposed oppositely to thecorresponding element adjustment device 45. The element diffusiondevices 55 are arranged on a virtual plane that is apart from theelement adjustment devices 45 by a certain distance. As shown in FIGS. 2and 3, each element diffusion device 55 is disposed oppositely to theelement adjustment device 45 along an optical axis of the unit lens 46constituting the corresponding element adjustment device 45. Namely, asshown in FIG. 1, similarly to the element adjustment devices 45, theelement diffusion devices 55 are arranged in a direction orthogonal tothe rotational axis line ra of the reflection device 21 constituting thelight scanner 20. As a result, the light diffusion device 50 extendslong in a direction orthogonal to the rotational axis line ra of thereflection device 21.

In addition, in the illustrated example, as shown in FIGS. 2 and 3, eachelement diffusion device 55 is located on a position based on therear-side focal point Bf of the unit lens 46 constituting thecorresponding element adjustment device 45. Herein, “a position based onthe rear-side focal point Bf” typically means that the each elementdiffusion device 55 is positioned on the rear-side focal point Bf.However, it is not exactly necessary that each element diffusion device55 is located on the rear-side focal point Bf. The element diffusiondevice 55 may be located in the vicinity of the rear-side focal pointBf. As described above, in the illustrated example, an emergent lightfrom each element adjustment device 45 travels along one of light pathsconstituting convergent light fluxes that converge on the rear-sidefocal point Bf. Thus, as shown in FIGS. 4 and 5, each element adjustmentdevice 45 and each element diffusion device 55 allows a laser light toenter the limited irradiation area IS of the corresponding elementdiffusion device 55, irrespective of an incident position of the laserlight on the element adjustment device 45.

In the example shown in FIG. 1, correspondingly to the fact that thelaser light source 15 has the first to third light source units 17 a, 17b and 17 c, the light diffusion device 50 has a first light diffusiondevice 50 a, a second light diffusion device 50 b and a third lightdiffusion device 50 c. A laser light from the first light source unit 17a enters the first light diffusion device 50 a, a laser light from thesecond light source unit 17 b enters the second light diffusion device50 b, and a laser light from the third light source unit 17 c enters thethird light diffusion device 50 c. By using laser lights that haveentered the respective light diffusion devices 50 a, 50 b and 50 c so asto be diffused, the one and the same illumination area Z can beilluminated. Thus, the first light diffusion device 50 a directs the redlight from the first light source unit 17 a toward the illumination areaZ, the second light diffusion device 50 b directs the green light fromthe second light source unit 17 b toward the illumination area Z, andthe third light diffusion device 50 c directs the blue light from thethird light source unit 17 c toward the illumination area Z, whereby theillumination area Z can be illuminated in white.

FIG. 5 is a schematic view in which the light-path adjustment device 40,the light diffusion device 50, and the element illumination areas Zp arerelated to each other. In the example shown in FIG. 5, the light-pathadjustment device 40 includes four element adjustment devices 45 thatare linearly arranged. Thus, the light diffusion device 50 includes fourelement diffusion devices 55 that are linearly arranged. Theillumination area Z is planarly divided into four element illuminationareas Zp1 to Zp4 which are arranged in a lattice pattern (grid pattern).Namely, in the illustrated example, one element illumination area Zp isnot overlapped with the other element illumination areas Zp. The firstelement diffusion devices 55 a of the respective light diffusion devices50 a, 50 b and 50 c illuminate the first element illumination area Zp1.Similarly, the second to fourth element diffusion devices 55 b, 55 c and55 d of the respective light diffusion devices 50 b, 50 c and 50 dilluminate the element illumination areas Zp2, Zp3 and Zp4,respectively.

The light diffusion device 50 is formed with the use of a hologramstorage medium 52, for example. In the example shown in FIG. 1, threehologram storage media 52 a, 52 b and 52 c are provided correspondinglyto the respective light diffusion devices 50 a, 50 b and 50 c. Therespective hologram storage media 52 are provided correspondingly tolaser lights of different wavelength ranges. By using laser lights ofdifferent wavelength ranges which have entered the whole area of therespective hologram storage media 52 so as to be diffused, the one andthe same illumination area Z can be illuminated.

Each hologram storage medium 52 is segmented into element diffusiondevices 55. The respective element diffusion devices 55 are formed ofelement holograms 57 storing interference fringe patters different fromone another. A laser light incident on each element hologram 57 isdiffracted by an interference fringe pattern, and illuminates acorresponding element illumination area Zp. Note that a diffusion lightdf that is diffused by the element hologram 57 at a certain instantilluminates only a part in the element illumination area Zp. Since anincident angle β of an incident light on the element hologram 57changes, an emergent angle γ from the element hologram 57 varies,whereby the whole area in the element illumination area Zp can beilluminated.

Generally, when a wavelength of a laser light (coherent light) incidenton the hologram storage medium is represented as “λ”, an incident angleof the laser light on the hologram storage medium is represented as “x”,an emergent angle (diffraction angle) of the laser light from thehologram storage medium is represented as “y”, and a microstructurepitch (diffraction pitch) of the hologram storage medium is representedas “p”, a relational expression “sin(x)±sin(y)=λ/p” is established.Thus, in a case where the light diffusion Device 50 has a hologramstorage medium, when the microstructure pitch p of the hologram storagemedium is constant and the wavelength λ of the laser light is constant,“λ/p” in the above relational expression become a constant. Thus, it canbe understood that the emergent angle y of the laser light variesdepending on the incident angle x thereof, from the aforementionedrelational expression. In addition, when the element diffusion device 55formed of the element hologram 57, by variously adjusting theinterference fringe patterns stored in the element hologram 57, atraveling direction of a laser light that is diffracted by each elementhologram 57, in other words, a traveling direction of a laser light dfthat is diffused and deflected by each element hologram 57 can becontrolled.

The element hologram 57 can be manufactured as a volume type hologram,for example. To be more specific, when a hologram photosensitivematerial that is a matrix of the element hologram 57 is irradiated witha reference light and an object light of a coherent light interferingwith each other, interference fringes by the light interference areformed on the hologram photosensitive material so that the elementhologram 57 is manufactured. By emitting a laser light toward theelement diffusion device 55 such that the laser light travels reverselyto the light path of the reference light that was used when the elementhologram 57 was manufactured, a diffraction light goes out from theelement hologram 57 reversely along the light path of the object lightthat was used when the element hologram 57 was manufactured.

Instead of being formed by using a real object light and a referencelight, a complicated interference fringe pattern formed on each elementhologram 57 can be designed by using a computer based on a wavelengthand an incident direction of expected illumination light as well as ashape and a positon of an image to be reconstructed. An element hologram57 thus obtained is also referred to as computer generated hologram(CGH). In addition, a Fourier conversion hologram in which respectivepoints on each element hologram 57 have the same diffusion angleproperties may be generated by a computer. Further, a size and aposition of an actual illumination range may be set by disposing anoptical member such as a lens behind an optical axis of an elementillumination area Zp.

One of the advantages of providing the element hologram 57 as theelement diffusion device 55 is that a light energy density of laserlight can be decreased by diffusion. Another advantage is that theelement hologram 57 can be used as a directional surface light source.In this case, as compared with a conventional lamp light source (pointlight source), a luminance on a light source surface for achieving thesame illumination distribution can be decreased. Thus, safety of laserlight can be improved. Namely, even when a person looks a laser lighthaving passed through the element illumination area Zp with his/hereyes, the eyes are less affected as compared with a case in which aperson looks a single point light source with his/her eyes.

Next, an operation of the illumination device 10 as structured above isdescribed.

As shown in FIG. 1, based on a control signal from the control unit 12,the respective light source units 17 a, 17 b and 17 c oscillate laserlights (laser beams) of respective wavelength ranges. Laser lightsemitted from the laser light source 15 firstly travel toward thereflection device 21 constituting the light scanner 20.

The reflection device 21 is continuously rotated about the rotationalaxis line ra. Thus, the six reflection surfaces 22 a to 22 f included inthe reflection device 21 reach a laser light irradiation position inseries. Each of the reflection surfaces 22 a to 22 f changes itsorientation at the incident position. Thus, the laser light reflected bythe reflection device 21 travels toward the light condensing device 30along one of light paths constituting divergent light fluxes whosedivergent point is the reflection position of the laser light. In theillustrated example, the reflection point of the reflection device 21 islocated on a position based on the front-side focal point Ff of thelight condensing lens 31 constituting the light condensing device 30.Thus, the light reflected by the reflection device 21 is deflected bythe light condensing lens 31 so as to travel toward the light-pathadjustment device 40 along one of light paths constituting parallellight fluxes traveling in a direction parallel to the optical axis ofthe light condensing lens 31.

Each of the reflection surfaces 22 a to 22 f of the reflection device 21changes its orientation such that an angle defined with respect to theincident direction of the laser light continuously decreases orincreases at the incident position. Thus, incident positions of thelaser light whose light path has been changed by the light scanner 20 onthe light condensing device 30 and the light-path adjustment device 40toward which the laser light then travels move in a direction notparallel to the rotational axis line ra, in particular, in theillustrated example, in a direction orthogonal to the rotational axisline ra in one orientation. In addition, angles defined by therespective reflection surfaces 22 a to 22 f included in the reflectiondevice 21 with respect to the rotational axis line ra differ from oneanother. Thus, the laser lights reflected by the different reflectionsurfaces 22 a to 22 f enter the light condensing device 30 and thelight-path adjustment device 40 toward which the laser lights thentravel, at different positions from one another in a direction parallelto the rotational axis line ra.

FIGS. 4 and 5 show the variation of an incident position on thelight-path adjustment device 40. A path p1 shows a variation of anincident position of a laser light, which has been reflected by thefirst reflection surface 22 a of the reflection device 21, on thelight-path adjustment device 40. Similarly, paths p2 to p6 showvariations of incident positions of laser lights, which have beenreflected by the second reflection surface 22 b to the sixth reflectionsurface 22 f. Since the reflection device is continuously rotated aboutthe rotational axis line ra, laser lights are reflected in series by thefirst reflection surface 22 a to the sixth reflection surfaces 22 f. Atthis time, an incident position of the laser light on the light-pathadjustment device 40 moves in series along the path p1, the path p2, thepath p3, the path p4, the path p5 and the path p6, and further repeatsthe change from the path p1 to the path p6. As apparent from FIGS. 4 and5, the laser light reflected by one reflection surface 22 scans inseries the first element adjustment device 45 a, the second elementadjustment device 45 b, the third element adjustment device 45 c and thefourth element adjustment device 45 d, which are included in thelight-path adjustment device 40.

A light path of the light incident on the light-path adjustment device40 is adjusted by each element adjustment device 45 constituting thelight-path adjustment device 40. In the illustrated example, the lightis incident on each element adjustment device 45 from a certaindirection. Thus, laser lights incident on respective positions of theelement adjustment device 45 converge at a positon apart therefrom by afocal distance f₄₅ of the element adjustment device 45. Namely, thelaser lights incident on the respective positions of one elementadjustment device 45 go out therefrom at emergent angels different fromone another.

Thereafter, the laser light whose light path has been adjusted by thelight-path adjustment device 40 enters the light diffusion device 50. Inparticular, the laser light, whose light path has been adjusted by eachelement adjustment device 45 of the light-path adjustment device 40,enters the element diffusion device 55 corresponding to the elementadjustment device 45. In the illustrated example, each element diffusiondevices 55 constituting the light diffusion device 50 is located on aposition apart from the corresponding element adjustment device 45 by afocal distance f₄₅ of the unit lens 46 constituting the elementadjustment device 45, in particular, a position based on the rear-sidefoal point Bf. Thus, the laser light enters the limited irradiation areaIS of each element diffusion device 55.

As described above, emergent angles α of laser lights going out fromrespective positions of one element adjustment device 45 differ from oneanother. Each element diffusion device 55 diffuses the laser light, anddirect the diffused light df to a direction depending on incident anglesβ of the laser light. The diffused light df travels toward the elementillumination area Zp corresponding to the element diffusion device 55 soas to illuminate the element illumination area Zp.

As has been already described with reference to FIG. 5, the elementdiffusion devices 55 included in one light diffusion device 50respectively illuminate the element illumination areas Zp that are atleast partially different from one another. In addition, as shown inFIG. 5, a laser light that has entered the element diffusion device 55at a certain instant illuminates only a spot area SA corresponding to apart of the element diffusion device 55. Namely, laser lights havingentered the one element diffusion device 55 at different incident anglesβ are diffused by the element diffusion device 55 and then illuminatethe spot areas SA different from one another in the element illuminationarea Zp. An incident angle β of the incident light on each elementdiffusion device 55 varies depending on an incident position at whichthe light is incident on the element adjustment device 45. In accordancewith the variation of the incident angle β on the element diffusiondevice 55, an emergent angle γ from the element diffusion device 55varies, whereby the spot area SA is moved through the whole area in theelement illumination area Zp. Thus, the whole area in one elementillumination area Zp corresponding to one element diffusion device 55can be illuminated.

FIG. 5 is a schematic view in which the light-path adjustment device 40,the light diffusion device 50, and the element illumination areas Zp arerelated to each other. In the example shown in FIG. 5, due to thereflection on the first reflection surface 22 a of the light scanner 20,the laser light scans the light-path adjustment device 40 along the pathp1. At this time, the laser light scans the first element adjustmentdevice 45 a included in the light-path adjustment device 40, then scansthe second element adjustment device 45 b, thereafter scans the thirdelement adjustment device 45 c, and finally scans the fourth elementadjustment device 45 d.

When the laser light scans the first element adjustment device 45 a, anincident angle β at which the laser light enters the first elementdiffusion device 55 a continuously changes. In accordance therewith, anemergent angle γ of the diffused light df, which has been diffused bythe first element diffusion device 55 a, from the first elementdiffusion device 55 a, changes such that the spot area SA scans thefirst element illumining area Zp1. Similarly, the laser light incidenton the second element adjustment device 45 b to scan the same along thepath 1 is then diffused by the second element diffusion device 55 b, andan emergent angle γ of the laser light from the second element diffusiondevice 55 b changes such that the spot area SA scans the second elementillumination area Zp2. In addition, the laser light incident on thethird element adjustment device 45 c to scan the same along the path p1is then diffused by the third element diffusion device 55 c, and anemergent angle γ of the laser light from the third element diffusiondevice 55 c changes such that the spot area SA scans the third elementillumination area Zp3. Further, the laser light incident on the fourthelement adjustment device 45 d to scan the same along the path p1 isthen diffused by the fourth element diffusion device 55 d, and anemergent angle γ of the laser light from the fourth element diffusiondevice 55 d changes such that the spot area SA scans the fourth elementillumination area Zp4.

Namely, in the specific example shown in FIG. 5, when the laser light isincident on the light-path adjustment device 40 to scan the light-pathadjustment device 40 along the path p1, the spot area SA of the diffusedlight df scans the illumination area Z in the order of a path p1-1 and apath p1-2. At this time, the diffused light df illuminates a first areaZp1-1 of the first element illumination area Zp1, a first area Zp2-1 ofthe second element illumination area Zp2, a first area Zp3-1 of thethird element illumination area Zp3 and a first area Zp4-1 of the fourthelement illumination area Zp4, in this order.

Similarly, in the specific example shown in FIG. 5, when the laser lightis incident on the light-path adjustment device 40 to scan thelight-path adjustment device 40 along the path p2, the spot area SA ofthe diffused light df scans the illumination area Z in the order of apath p2-1 and a path p2-2. At this time, the diffused light dfilluminates a second area Zp1-2 of the first element illumination areaZp1, a second area Zp2-2 of the second element illumination area Zp2, asecond area Zp3-2 of the third element illumination area Zp3 and asecond area Zp4-2 of the fourth element illumination area Zp4, in thisorder.

Similarly thereafter, when the laser light is incident on the light-pathadjustment device 40 to scan the light-path adjustment device 40 alongthe path p3, the spot area SA of the diffused light df scans theillumination area Z in the order of a path p3-1 and a path p3-2. At thistime, the diffused light df illuminates a third area Zp1-3 of the firstelement illumination area Zp1, a third area Zp2-3 of the second elementillumination area Zp2, a third area Zp3-3 of the third elementillumination area Zp3 and a third area Zp4-3 of the fourth elementillumination area Zp4, in this order.

Next, when the laser light is incident on the light-path adjustmentdevice 40 to scan the light-path adjustment device 40 along the path p4,the spot area SA of the diffused light df scans the illumination area Zin the order of a path p4-1 and a path p4-2. At this time, the diffusedlight df illuminates a first area Zp1-4 of the fourth elementillumination area Zp1, a fourth area Zp2-4 of the second elementillumination area Zp2, a fourth area Zp3-4 of the third elementillumination area Zp3 and a fourth area Zp4-4 of the fourth elementillumination area Zp4, in this order.

Thereafter, when the laser light is incident on the light-pathadjustment device 40 to scan the light-path adjustment device 40 alongthe path p5, the spot area SA of the diffused light df scans theillumination area Z in the order of a path p5-1 and a path p5-2. At thistime, the diffused light df illuminates a fifth area Zp1-5 of the firstelement illumination area Zp1, a fifth area Zp2-5 of the second elementillumination area Zp2, a fifth area Zp3-5 of the third elementillumination area Zp3 and a fifth area Zp4-5 of the fourth elementillumination area Zp4, in this order.

Next, when the laser light is incident on the light-path adjustmentdevice 40 to scan the light-path adjustment device 40 along the path p6,the spot area SA of the diffused light df scans the illumination area Zin the order of a path p6-1 and a path p6-2. At this time, the diffusedlight df illuminates a sixth area Zp1-6 of the first elementillumination area Zp1, a sixth area Zp2-6 of the second elementillumination area Zp2, a sixth area Zp3-6 of the third elementillumination area Zp3 and a sixth area Zp4-6 of the fourth elementillumination area Zp4, in this order.

In the illustrated example, the path p1 in the light-path adjustmentdevice 40 is parallel to and opposite (reverse) to the path p1-1 and thepath p1-2 in the illumination area Z. Similarly, the paths p2 to p6 inthe light-path adjustment device 40 are parallel to and opposite(reverse) to the corresponding paths in the illumination area Z. Inaddition, a direction in which the paths p1 to p6 are arranged in thelight-path adjustment device 40 is parallel to a direction in which thepaths p1-1 to p6-1 are arranged and a direction in which the paths p1-2to p6-2 are arranged, in each element illumination area Zp. However, adirection in which the paths p1 to p6 in the light-path adjustmentdevice 40 are arranged is parallel to and opposite (reverse) to adirection in which the paths p1-1 to p6-1 in each element illuminationarea Zp are arranged, and is parallel to and opposite (reverse) to adirection in which the paths p1-2 to p6-2 are arranged. In addition, adirection in which the paths p1 to p6 in the light-path adjustmentdevice 40 are arranged is parallel to and opposite (reverse) to adirection in which the first area Zp1-1 to the sixth area Zp1-6 in thefirst element illumination area Zp1 are arranged, parallel to andopposite (reverse) to a direction in which the first area Zp2-1 to thesixth area Zp2-6 in the second element illumination area Zp2 arearranged, parallel to and opposite (reverse) to a direction in which thefirst area Zp3-1 to the sixth area Zp3-6 in the third elementillumination area Zp3 and are arranged, and parallel to and opposite(reverse) to a direction in which the first area Zp4-1 to the sixth areaZp4-6 in the fourth element illumination area Zp4 are arranged.

In the aforementioned embodiment, the illumination device 10 includesthe light source 15, the light scanner 20 capable of changing a lightpath of light-source light emitted from the light source, the lightdiffusion device 50 having element diffusion devices 55 that diffuse thelight-source light, and the light-path adjustment device disposed on alight path of the light-source light from the light scanner 20 up to thelight diffusion device 50. The light-path adjustment device 40 has theelement adjustment devices 45 that are provided correspondingly to therespective element diffusion devices 55, and adjust a light path of thelight-source light toward the corresponding element diffusion devices55. An incident position of the light-source light on the light-pathadjustment device 40 varies depending on a light path determined by thelight scanner 20. Each element diffusion device 55 illuminates anelement illumination area Zp corresponding to the element diffusiondevice 55.

Namely, according to this embodiment, the light diffusion device 50includes the element diffusion devices 55, and each element diffusiondevice 55 can diffuse an incident light in a diffusion pattern or alight distribution pattern different from that of the other elementdiffusion devices 55. Thus, the element illumination area Zpconstituting a part of the illumination area Z can be illuminated by adiffused light going out from one element diffusion device 55.Accordingly, the illumination area Z is segmented into the elementillumination areas Zp so that a pattern illumination of each of theelement illumination areas Zp can be achieved. By controlling emissionof light by the light source 15 depending on the scanning of thelight-source light on the light-path adjustment device 40 by means ofthe light scanner 20, in other words, depending on an incident positionof the light-source light on the light-path adjustment device 40, thepattern illumination can be realized easily and stably.

In addition, according to this embodiment, an emergent angle α of thelight-source light from each element adjustment device 45 and, inaccordance therewith, an incident angle β of the light-source light oneach element diffusion device 55 vary depending on an incident positionon the element adjustment device 45 corresponding to the elementdiffusion device 55. In addition, an emergent angle γ from each elementdiffusion device 55 varies depending on the incident angle β on theelement diffusion device 55. Thus, by controlling emission of light bythe light source depending on the scanning of the light-source light onone element adjustment device 45 by means of the light scanner 20, inother words, depending on an incident position of the light-source lighton one element adjustment device 45, a pattern illumination in only adesired area constituting a part of the element illumination area Zpcorresponding to one element diffusion device 55 can be achieved.According to such an embodiment, as compared with a case in which theelement illumination area Zp is segmented into areas and additionalelement diffusion devices are provided on the respective areas, thestructure and control of the illumination device can be significantlysimplified.

From above, according to this embodiment, since illumination of theelement illumination area Zp constituting a part of he illumination areaZ is carried out by each element diffusion device 55 included in thelight diffusion device 50, rough pattern illumination of theillumination area Z can be realized. Further, since an incident angle βof the light-source light on each element diffusion device 55 can bechanged according to an incident position of the light-source light oneach element adjustment device 45 included in the light-path adjustmentdevice 40, an emergent direction of the diffused light from each elementdiffusion device 55 can be changed. Thus, by controlling an incidentposition of the light-source light on the light-path adjustment device40, not only a pattern illumination of each of the element illuminationareas Zp can be achieved, but also a pattern illumination in eachelement illumination area Zp can be achieved. Namely, according to theillumination device 10 in this embodiment, a high definition lightdistribution pattern can be realized by a simple structure using thelight diffusion device 50 including the limited number of elementdiffusion devices 55.

In addition, according to this embodiment, the element illuminationareas Zp corresponding to the respective element diffusion devices 55are not overlapped with one another. Thus, a pattern illumination of theillumination area Z can be precisely performed, while only apredetermined element illumination area Zp can be illuminated.

In this embodiment, the light scanner 20 has the rotatable reflectiondevice 21, the reflection device 21 includes the reflection surfaces 22at positions surrounding its rotational axis line ra, and an angledefined by one reflection surface 22 included in the reflection surfaces22 with respect to the rotational axis line ra differs from an angledefined by at least another reflection surface 22 included in thereflection surfaces 22 with respect tot the rotational axis line ra.According to such an embodiment, by the significantly easy operation,i.e., by rotating the reflection device 21 of a simple structure,incident positions of the light-source light on the incident surface ofthe light-path adjustment device 40 and on the incident surface of thelight diffusion device 50 can be changed two-dimensionally. In addition,since the incident positions of the light-source light on the incidentsurface of the light-path adjustment device 40 and on the incidentsurface of the light diffusion device 50 can be changedtwo-dimensionally, an emergent direction of the diffused light from thelight diffusion device 50 can be changed two-dimensionally. As a result,it is possible to two-dimensionally change a light distribution patternin the element illumination area Zp by the illumination device of asimple structure and a simple operation.

In this embodiment, the illumination device 10 further has the lightcondensing device 30 disposed on a light path of the light-source lightform the light scanner 20 up to the light-path adjustment device 40.According to such a illumination device 10, for example, light paths oflights toward the whole area of one element adjustment device 45,further light paths of lights toward the whole area of the light-pathadjustment device 40 can be made parallel. In this case, the light-pathadjustment device 40 allows an emergent direction of the light-sourcelight incident thereon from a predetermined direction to be changed intoa desired direction highly precisely. Thus, a light distribution patternof a high definition can be controlled highly precisely.

In this embodiment, the light scanner 20 is located on a position basedon the front-side focal point Ff of the light condensing device 30.Thus, the light condensing device 30 allows lights, whose light pathsare changed by the light scanner 20 to enter respective positions of thelight condensing device 30 at different incident angles, to travel insubstantially a certain direction. Therefore, the light path adjustmentcan be more precisely performed by the light-path adjustment device 40,whereby a light distribution pattern of a high definition can becontrolled highly precisely.

In this embodiment, the light-path adjustment device 40 is a lens array41 including the unit lenses 46 constituting the element adjustmentdevices 45. Namely, the light-path adjustment device 40 has a simplestructure, and can be manufactured at low costs. In addition, incombination with the light condensing lens 31, a light path of a lightincident on the lens array 41 constituting the light-path adjustmentdevice 40 can be adjusted highly precisely.

In this embodiment, each element diffusion device 55 is located on aposition based on the rear-side focal point Bf of the unit lens 46constituting a corresponding element adjustment device 45. Thus, after alight path of a light, which was incident on each positon of the elementadjustment device 45, is adjusted by the element adjustment device 45,the light enters the limited irradiation area IS on the elementdiffusion device 55 in the vicinity of the rear-side focal point Bf.Thus, the diffused light df illuminating the element illumination areaZp goes out from the specific area IS of each element diffusion device55. Thus, by controlling an emergent direction of the diffused lightgoing out from the element diffusion device 55, a pattern illuminationin the element illumination area Zp can be highly precisely achieved ina light distribution pattern of a high definition.

The above-described embodiment can be variously modified. A modificationexample is described herebelow. In the below description, a componentthat can be similarly structured as that of the above embodiment has thesame reference number as the number used for the corresponding componentof the above embodiment, and redundant description is omitted.

In the above-described embodiment, the light diffusion device 50 isformed of the hologram storage media 52, but the present invention isnot limited to this example. For example, the light diffusion device 50may be formed of a lens array group 53 having each element diffusiondevice 55 as one lens array 58. In this case, the lens array 58 isprovided on every element diffusion device 55, and the shape of eachlens array 58 is designed such that each lens array 58 illuminates anelement illumination area Zp in the illumination area Z.

In addition, in the above-described embodiment, the light-pathadjustment device 40 is formed of the lens array 41, and the elementadjustment device 45 is formed of the unit lens 46 of the lens array 41,but the present invention is not limited to this example. the light-pathadjustment device 40 may further include an auxiliary adjustment devicefor adjusting an optical axis of a light flux shaped by each unit lens.As the auxiliary adjustment device, a prism array including unit prismsprovided correspondingly to the respective unit lenses 46, or adiffraction grating array including diffraction gratings providedcorrespondingly to the respective unit lenses 46 may be used. Inaddition, the light-path adjustment device 40 may be a hologram storagemedium, and the element adjustment devices 45 may be element hologramshaving interference fringe patterns different from one another.

Further, in the above-described embodiment, the light condensing deviceis formed of a convex lens, but the present invention is not limited tothis example. For example, the light condensing device 30 may be formedof a concave mirror.

Further, in the above-described embodiment, the laser light source 15 asa light source emits laser lights of a plurality of wavelength ranges,but the present invention is not limited to this example. The lightsource may be a light source that emits lights of the same wavelengthrange.

Further, the above-described illumination device 10 may be mounted on aconveyance, or installed at a predetermined location. When it is mountedon a conveyance, the conveyance may be various moving bodies such as avehicle like an automobile, a flying body like an aircraft, a train, aship, a diving body and so on.

Although some modification examples of the second embodiment have beendescribed above, the modification examples can be naturally combined andused.

1. An illumination device comprising: a light source; a light scannercapable of changing a light path of light-source light emitted from thelight source; a light diffusion device having element diffusion devicesthat diffuse the light-source light; a light-path adjustment devicedisposed on a light path of the light-source light from the lightscanner up to the light diffusion device, the light-path adjustmentdevice having element adjustment devices that are providedcorrespondingly to the respective element diffusion devices, and adjusta light path of the light-source light toward the corresponding elementdiffusion devices; and a control unit that controls emission timing ofthe light-source light, or illumination timing of the illumination area,wherein: an incident position of the light-source light on thelight-path adjustment device varies depending on a light path determinedby the light scanner; an incident angle of the light-source light oneach element diffusion device varies depending on an incident positionon the element adjustment device corresponding to the element diffusiondevice; an emergent angle from each element diffusion device variesdepending on the incident angle; and each element diffusion deviceilluminates an element illumination area corresponding to the elementdiffusion device; the light source includes a first light source unitand a second light source unit; and the control unit controls theemission timing or illumination timing of light-source light emittedfrom the first light source unit, independently from the emission timingor illumination timing of light-source light emitted from the secondlight source unit.
 2. The illumination device according to claim 1,wherein light emitted from each element adjustment device travels alongone of light paths of convergent light fluxes to enter an elementdiffusion device corresponding to the element adjustment device.
 3. Theillumination device according to claim 1, wherein element illuminationareas corresponding to the respective element diffusion devices are notoverlapped with one another.
 4. The illumination device according toclaim 1, wherein: the light scanner has a rotatable reflection device;the reflection device includes reflection surfaces at positionssurrounding its rotational axis line; and an angle defined by onereflection surface included in the reflection surfaces with respect tothe rotational axis line differs from an angle defined by at leastanother reflection surface included in the reflection surfaces withrespect to the rotational axis line.
 5. The illumination deviceaccording to claim 1, further comprising a light condensing devicedisposed on a light path of the light-source light from the lightscanner up to the light-path adjustment device.
 6. The illuminationdevice according to claim 1, wherein the light-path adjustment devicehas a lens array including unit lenses constituting the elementadjustment devices.
 7. The illumination device according to claim 6,wherein each element diffusion device is located on a position based ona rear-side focal point of a unit lens constituting a correspondingelement adjustment device.
 8. The illumination device according to claim1, wherein each element adjustment device allows the light-source lightto enter a specific area of a corresponding element diffusion device,irrespective of an incident position of the light-source light on theelement adjustment device.
 9. The illumination device according to claim1, wherein the light diffusion device has a hologram storage medium, andthe element diffusion devices are element holograms includinginterference fringe patterns different from one another.
 10. Theillumination device according to claim 1, wherein the light diffusiondevice has a lens array group having lens arrays constituting theelement diffusion devices.
 11. (canceled)
 12. The illumination deviceaccording to claim 1, wherein the first light source unit emits lighthaving a wavelength range different from that emitted by the secondlight source unit.
 13. The illumination device according to claim 1,wherein the light source further includes a third light source unit, andthe first light source unit oscillates light having a red emissionwavelength range, the second light source unit oscillates light having agreen emission wavelength range, and the third light source unitoscillates light having a blue emission wavelength range.
 14. Theillumination device according to claim 1, wherein the element diffusiondevices and the element adjustment devices are arranged along onedirection; and the element illumination areas illuminated by the elementdiffusion devices are arranged in two directions different from eachother.
 15. The illumination device according to claim 4, wherein theelement illumination areas are arranged in a lattice pattern.
 16. Theillumination device according to claim 1, wherein the element diffusiondevices and the element adjustment devices are arranged along onedirection; and the element illumination areas illuminated by the elementdiffusion devices are arranged in a direction which is nonparallel tothe one direction.